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Official Description

Alpha-fetoprotein (AFP); serum

© Copyright 2026 American Medical Association. All rights reserved.

Common Language Description

Alpha-fetoprotein (AFP) is a crucial biomarker measured in serum to assess fetal health during pregnancy. This protein is initially produced by the yolk sac of the developing fetus and later by the liver and gastrointestinal tract as gestation progresses. The measurement of AFP levels in maternal serum is particularly significant between the 14th and 22nd weeks of pregnancy, as it serves as a screening tool for various fetal conditions. Elevated levels of AFP can indicate the presence of neural tube defects, such as spina bifida and anencephaly, which are serious congenital malformations. Conversely, low levels of AFP may suggest chromosomal abnormalities, including Down syndrome (trisomy 21) and Edwards syndrome (trisomy 18), as well as conditions like omphalocele. The procedure for obtaining the serum sample involves a venipuncture, which is a separate reportable service. The results of the AFP test provide valuable information that can guide further diagnostic testing and management of the pregnancy.

© Copyright 2026 Coding Ahead. All rights reserved.

1. Indications

Alpha-fetoprotein (AFP) testing is indicated for the following conditions:

  • Neural Tube Defects High levels of AFP in the serum may indicate the presence of neural tube defects such as spina bifida and anencephaly.
  • Chromosomal Abnormalities Low levels of AFP can suggest chromosomal abnormalities, including Down syndrome (trisomy 21) and Edwards syndrome (trisomy 18).
  • Omphalocele The presence of elevated AFP levels may also be associated with omphalocele, a congenital defect where the infant's intestines or other abdominal organs protrude through the abdominal wall.

2. Procedure

The procedure for measuring alpha-fetoprotein (AFP) in serum involves several key steps:

  • Step 1: Patient Preparation The patient is typically advised to schedule the blood draw between the 14th and 22nd weeks of gestation. It is important to ensure that the patient understands the purpose of the test and what to expect during the venipuncture process.
  • Step 2: Venipuncture A qualified healthcare professional performs a venipuncture to obtain a blood sample from the patient. This step is crucial as it allows for the collection of serum, which will be analyzed for AFP levels. The venipuncture should be performed using standard aseptic techniques to minimize the risk of infection.
  • Step 3: Serum Separation After the blood sample is collected, it is processed to separate the serum from the cellular components. This is typically done by centrifugation, which allows the serum to be isolated for testing.
  • Step 4: Laboratory Analysis The separated serum is then sent to a laboratory where it undergoes analysis to measure the concentration of alpha-fetoprotein. The results will indicate whether the AFP levels are within the normal range or if they are elevated or decreased, which can suggest potential fetal abnormalities.

3. Post-Procedure

After the AFP serum test is completed, the patient may resume normal activities. It is important for the healthcare provider to discuss the results with the patient once they are available. If the AFP levels are found to be abnormal, further diagnostic testing may be recommended, such as amniocentesis, to obtain more definitive information regarding the fetal condition. The patient should be informed about the implications of the test results and any necessary follow-up actions that may be required based on the findings.

Short Descr ALPHA-FETOPROTEIN SERUM
Medium Descr ALPHA-FETOPROTEIN SERUM
Long Descr Alpha-fetoprotein (AFP); serum
Status Code Statutory Exclusion (from MPFS, may be paid under other methodologies)
Global Days XXX - Global Concept Does Not Apply
PC/TC Indicator (26, TC) 9 - Not Applicable
Multiple Procedures (51) 9 - Concept does not apply.
Bilateral Surgery (50) 9 - Concept does not apply.
Physician Supervisions 09 - Concept does not apply.
Assistant Surgeon (80, 82) 9 - Concept does not apply.
Co-Surgeons (62) 9 - Concept does not apply.
Team Surgery (66) 9 - Concept does not apply.
Diagnostic Imaging Family 99 - Concept Does Not Apply
CLIA Waived (QW) No
APC Status Indicator Conditionally packaged laboratory tests
Type of Service (TOS) 5 - Diagnostic Laboratory
Berenson-Eggers TOS (BETOS) T1H - Lab tests - other (non-Medicare fee schedule)
MUE 1
CCS Clinical Classification 233 - Laboratory - Chemistry and Hematology
GA Waiver of liability statement issued as required by payer policy, individual case
90 Reference (outside) laboratory: when laboratory procedures are performed by a party other than the treating or reporting physician or other qualified health care professional, the procedure may be identified by adding modifier 90 to the usual procedure number.
GZ Item or service expected to be denied as not reasonable and necessary
Q4 Service for ordering/referring physician qualifies as a service exemption
Q1 Routine clinical service provided in a clinical research study that is in an approved clinical research study
GW Service not related to the hospice patient's terminal condition
GY Item or service statutorily excluded, does not meet the definition of any medicare benefit or, for non-medicare insurers, is not a contract benefit
QJ Services/items provided to a prisoner or patient in state or local custody, however the state or local government, as applicable, meets the requirements in 42 cfr 411.4 (b)
26 Professional component: certain procedures are a combination of a physician or other qualified health care professional component and a technical component. when the physician or other qualified health care professional component is reported separately, the service may be identified by adding modifier 26 to the usual procedure number.
59 Distinct procedural service: under certain circumstances, it may be necessary to indicate that a procedure or service was distinct or independent from other non-e/m services performed on the same day. modifier 59 is used to identify procedures/services, other than e/m services, that are not normally reported together, but are appropriate under the circumstances. documentation must support a different session, different procedure or surgery, different site or organ system, separate incision/excision, separate lesion, or separate injury (or area of injury in extensive injuries) not ordinarily encountered or performed on the same day by the same individual. however, when another already established modifier is appropriate it should be used rather than modifier 59. only if no more descriptive modifier is available, and the use of modifier 59 best explains the circumstances, should modifier 59 be used. note: modifier 59 should not be appended to an e/m service. to report a separate and distinct e/m service with a non-e/m service performed on the same date, see modifier 25.
77 Repeat procedure by another physician or other qualified health care professional: it may be necessary to indicate that a basic procedure or service was repeated by another physician or other qualified health care professional subsequent to the original procedure or service. this circumstance may be reported by adding modifier 77 to the repeated procedure or service. note: this modifier should not be appended to an e/m service.
91 Repeat clinical diagnostic laboratory test: in the course of treatment of the patient, it may be necessary to repeat the same laboratory test on the same day to obtain subsequent (multiple) test results. under these circumstances, the laboratory test performed can be identified by its usual procedure number and the addition of modifier 91. note: this modifier may not be used when tests are rerun to confirm initial results; due to testing problems with specimens or equipment; or for any other reason when a normal, one-time, reportable result is all that is required. this modifier may not be used when other code(s) describe a series of test results (eg, glucose tolerance tests, evocative/suppression testing). this modifier may only be used for laboratory test(s) performed more than once on the same day on the same patient.
95 Synchronous telemedicine service rendered via a real-time interactive audio and video telecommunications system: synchronous telemedicine service is defined as a real-time interaction between a physician or other qualified health care professional and a patient who is located at a distant site from the physician or other qualified health care professional. the totality of the communication of information exchanged between the physician or other qualified health care professional and the patient during the course of the synchronous telemedicine service must be of an amount and nature that would be sufficient to meet the key components and/or requirements of the same service when rendered via a face-to-face interaction. modifier 95 may only be appended to the services listed in appendix p. appendix p is the list of cpt codes for services that are typically performed face-to-face, but may be rendered via a real-time (synchronous) interactive audio and video telecommunications system.
CC Procedure code change (use 'cc' when the procedure code submitted was changed either for administrative reasons or because an incorrect code was filed)
GV Attending physician not employed or paid under arrangement by the patient's hospice provider
GX Notice of liability issued, voluntary under payer policy
PD Diagnostic or related non diagnostic item or service provided in a wholly owned or operated entity to a patient who is admitted as an inpatient within 3 days
Q6 Service furnished under a fee-for-time compensation arrangement by a substitute physician or by a substitute physical therapist furnishing outpatient physical therapy services in a health professional shortage area, a medically underserved area, or a rural area
QW Clia waived test
TC Technical component; under certain circumstances, a charge may be made for the technical component alone; under those circumstances the technical component charge is identified by adding modifier 'tc' to the usual procedure number; technical component charges are institutional charges and not billed separately by physicians; however, portable x-ray suppliers only bill for technical component and should utilize modifier tc; the charge data from portable x-ray suppliers will then be used to build customary and prevailing profiles
XU Unusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service
Date
Action
Notes
2011-01-01 Changed Short description changed.
2007-01-01 Changed Code description changed.
1993-01-01 Added First appearance in code book in 1993.
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